For more than three years, countless reviews, investigations and commissions on the 9/11 attacks concentrated on the intelligence, law enforcement and broader foreign policy failures that allowed al-Qaida to strike a devastating blow at the United States that day. On Wednesday, at long last, the most important of these reviews finally turned its spotlight on the most comprehensive and startling failure of that day: the inability of the world’s most sophisticated air force to mount any significant defense against the attackers.

In the strictest sense, all other questions plumbed in the days since that awful Tuesday are about the context of the attacks, not their substance. Conflicting jurisdictions and missions bedeviled the CIA and other agencies, including those dealing with visas, borders, immigration and domestic surveillance. Even without these handicaps, perfect performance might still fall short.

Intelligence and law enforcement activities, even at their most competent and coordinated, might never glean the evil plans of a small group of well-disciplined attackers. Foreign policy at its most enlightened will still fail to dissuade those bent on blaming the world’s injustices (and their own culture’s myriad failures) on the dominant nation of the times. Even the Federal Aviation Administration, which repeatedly failed to do the right thing that day, can legitimately argue that its core mission did not include command and control of American air defenses.

“Regardless of the color of the plane or what flag it had on its tail, NORAD and the Air Force for 50 years have been tasked with the job of going up, intercepting them and making sure they never get close,” says Dan Goure, a senior defense official in the Reagan administration and now an NBC News military analyst. “No failure on 9/11 was more complete.”

Chasing ‘phantoms’
There are, as always, mitigating factors. The nation, and NORAD in particular, had relaxed its defenses after the fall of the Soviet Union. Domestic patrol tasks now fell to the Air National Guard rather than high-alert active duty units, and it had fewer bases (seven in 2001, as opposed to 27 in 1989). Some of NORAD’s domestic radar systems were turned over to the FAA. This last fact turned out to be devastating. Among other things, FAA failed repeatedly to pass warnings on to NORAD in a timely manner when it realized planes had been hijacked, and it wasted precious time by directing the Air Force’s first flight of F-15s to intercept American Airlines Flight 11, a plane that disappeared into a skyscraper before the warplanes even took off.

"We fought many phantoms that day," Air Force Gen. Richard Myers, chairman of the Joint Chiefs of Staff, told the commission.

Yet the Air Force remained responsible for securing American airspace to “Deter, Detect and Defend,” as its motto plainly states. As 9/11 commissioner Jamie Gorelick pointed out Wednesday, the charter does not limit the Air Force to defending the United States from attacks abroad, but also includes “providing surveillance and control of the airspace of Canada and the United States.”

Since 9/11, the Air Force’s defense of its performance that day has rested on three basic contentions:

A closer look
For the better part of three years, that story held up, in part due to a distinct lack of scrutiny, but also because the Air Force made it exceedingly difficult for anyone without a security clearance to ask questions about that day. Repeated requests by this columnist to interview some of the F-16 pilots scrambled on 9/11 were denied on the basis of "national security." Others were unavailable, quite reasonably, because of assignment overseas to fight in the Middle East.

“The process — what’s being called the ‘protocol’ — was an Air Force creature, by and large, and it failed spectacularly that day,” says an Air Force official, requesting anonymity. “If you had taken any intelligent American that day and put them in a chair and said, ‘OK, if anything strange happens, you make sure the White House, the Capitol and the Pentagon are protected,’ that person would have ordered fighters into the air over Washington at 9:03 a.m.,” the moment United Flight 175 hit the second trade center tower.

Unfortunately, the protocol designed by the military for making that happen turned out to be far too complicated and bureaucratic to be useful.

Point-by-point
Scrutinize the Air Force’s contentions point by point, and the degree of systemic failure begins to become clear.

Moment by momentAs Gorelick noted, the idea that NORAD exists to defend solely against foreign threats is simply untrue. While its long-time focus was a massive Soviet bomber or missile attack, it had years (and even bureaucratic incentive) to rethink and reinvent itself to suit contemporary realities.

Indeed, even after the Soviet collapse, NORAD managed on many occasions to perform its domestic functions capably. In 1999, when professional golfer Payne Stewart and his entourage apparently asphyxiated on board a private jet heading north on automatic pilot in the middle of American airspace, NORAD managed to get two warplanes astride it within an hour to ensure it would not come down in a populated area.

Another red herring is the idea that NORAD simply did not have the aircraft and radars it needed to respond properly. It is generally agreed, from a military standpoint, that the two strikes on the trade center in New York were unstoppable. But it has bothered military analysts ever since that 39 minutes later an identical attack succeeded in destroying part of the Pentagon, the nerve center of the world’s most powerful military.

F-16 and F-15 warplanes based at Langley Air Force Base in Virginia were within easy reach of Washington, and yet it appears it was not until after 9:38 am., when American Airlines Flight 77 slammed into the Pentagon, that Langley’s fighters went aloft.

“They should have been over Washington by that time,” says the Air Force official. “It did not happen that way.”

Another troubling fact: even after Vice President Richard Cheney gave the authorization to shoot down errant airliners, the order was held up by unexplained hesitancy in the Air Force chain of command. In effect, the pilots, had they even been on the scene, would not have had the key authorization in time anyway.

'Failure of imagination?'
What of the idea that no one could have imagined the use of airliners as weapons?

After Wednesday’s hearing, 9/11 commission co-chairman Lee Hamilton said: “One of the failures you have here, among others, is a failure of imagination. Our policy people were simply unable to imagine using an airplane as a weapon.”

Rebuilding the PentagonIn fact, anyone with a newspaper-level interest in foreign policy, counter-terrorism or the Islamic extremism knew by 1995 that just such a plan had been foiled by French commandos just before New Year’s Eve 1994. An Algerian group known as the GIA hijacked an Air France jetliner with the intention of flying it into the Eiffel Tower. After the terrorists executed a passenger, the plane was allowed to fly to Marseilles. During refueling there, French commandos stormed the plane and rescued all 177 passengers.

For an event like this to have escaped the notice of an agency charged with securing American airspace is hard to believe. That’s almost as hard to believe as the Pentagon being hit by a hijacked airliner 39 minutes after a second one struck the south tower of the World Trade Center.